Using an Environment-Friendly Fertiliser from Sewage Sludge Ash with the Addition of Bacillus megaterium

Abstract

Sewage sludge ash (SSA) is considered to be a valuable secondary raw material for the production of phosphorous fertilisers. This method of recycling may also be a solution to the problem posed by the growing amount of this waste. An innovative suspension fertiliser (SSAB) was produced from SSA and the phosphorus-solubilising bacteria Bacillus megaterium and was tested in a field experiment in the presence of spring wheat as the test plant in comparison to conventional fertilisers (superphosphate, phosphorite). Two variants of plant protection were also adopted: full chemical plant protection (+PP) and no plant protection (−PP). Besides affecting yield, it was expected that SSAB would not worsen the state of the soil environment. This paper presents SSAB effect on soil moisture and temperature, soil pH, content of toxic elements (As, Cd, Cr, Ni and Pb) in the soil, abundance of heterotrophic bacteria and fungi and the occurrence of earthworms. SSAB did not affect the tested soil characteristics when applied in reasonable doses. Plant protection had an individual effect on soil properties but did not modify the fertiliser action. SSAB may be a potential substitute for P fertilisers produced from non-renewable raw materials in times of shortage. Further long-term research is recommended to confirm these findings.